SAR Technical Description

SAR overview

SAR is the Stand Alone portion of the FDR DASD Management System. SAR is an IPL-able, self-loading, stand-alone program not requiring an operating system.

SAR enables you to BACKUP or RESTORE a DASD volume when, due to the unavailability of an operating system, FDR cannot be run. SAR may be used to recover or move DASD volumes after DASD failures or HDA replacements. SAR may also be used at disaster recovery sites or new primary sites to restore the DASD volumes necessary to IPL.

SAR is simple to use and provides console messages to prompt you, so there are no control cards to prepare. Diagnostic messages are issued if SAR encounters difficulty during the BACKUP or RESTORE.

SAR supports three major operations:

RESTORE—a DASD volume from a backup tape.
DUMP—an entire DASD volume or selected data sets to tape.
CLIP—to change the volume serial of a DASD volume in place.

Supported hardware

SAR executes on any CPU capable of running any version of z/OS and can execute in an LPAR or on a VM virtual machine.

SAR supports any Count-Key-Data (CKD) DASD supported by those operating systems, which means any real or emulated 3390 or 3380 DASD volume, regardless of the DASD subsystem manufacturer.

SAR supports any tape drive supported by z/OS.

SAR was made easy to use and fairly intuitive. For example, SAR displays the available choices for almost all options, and prompts you if you enter an invalid value. However, SAR is infrequently used and you are often rushed to complete the SAR operation, so mistakes are easily made. We have gathered common problems and solutions, as well as hints for usage, extracted from our years of SAR support. After reading the rest of the SAR documentation, please review SAR-Hints-and-Recommendations for suggestions on avoiding common problems.

SAR restrictions

SAR does not support Extended Address Volumes (EAVs).
SAR cannot restore tapes compressed by zEDC.
SAR cannot restore tapes created by FDRCRYPT.

SAR support for z14 processor

SAR has supported all architectures from S/360 through ESA/390. Up until now, SAR has run on the IBM Z® in ESA/390 mode. The new IBM z14 processor does not support ESA/390 mode. Therefore, to run SAR on the z14, you must use a new level of SAR. This support is available in Release 05.04.87 SPIN 3 or higher of FDR.

Important

Ensure that you are using the current version of FDRSARLR that contains this z14 support to create the loadable SAR module.

SAR restore operations

SAR can restore:

An entire DASD volume from a full-volume backup tape created by FDR, ABR, or SAR.
Ranges of specific tracks, from any type of backup tape created by FDR, DSF, ABR, or SAR.

If the input tape to a SAR restore is not a full-volume backup tape, SAR issues a warning message and the option to continue the restore. This usually means that the wrong tape was mounted.

SAR can only restore backups to the same DASD format, for example, 3380 to 3380, 3390 to 3390.

On a full-volume restore, there are 3 options controlling the volume serial of the DASD volume after the restore:

Retain the original volume serial of the output DASD volume
Restore the volume serial of the DASD volume on the backup tape
Specify a new volume serial from the console

SAR can restore to a volume that is not initialized, that is, one that does not currently contain a volume label or VTOC.

If you restore an ABR-created full-volume backup tape using SAR, the ABR Model DSCB on the volume is down-leveled. The Generation and Cycle reflects the previous generation. Use the REMODEL command. See FDRABRM-REMODEL-Statement) to update the ABR Model DSCB after you reIPL z/OS. You should not try to restore from an ABR-created incremental (data set) backup.

SAR can restore from any file on an ABR backup tape, using the file sequence number on the INPUT TAPE UNIT command. The file sequence number is shown in the FDRABRP PRINT CATLG report, and in the FDR305 message in the listing of the backup job. For more information, see ABR Backup Tapes in SAR-Hints-and-Recommendations.

Warning

SAR cannot restore encrypted backup tapes created by FDRCRYPT.

SAR backup operations

SAR can back up to tape:

An entire DASD volume (excluding extended address volumes (EAVs). The backup contains all allocated tracks as shown in the VTOC, including the VTOC and the label track (cylinder 0 track 0).
Data sets, by data set name or group name (similar to a DSF or ABR data set backup).
Ranges of specific tracks (similar to a backup created by DSF with FROM/TO).

SAR requests scratch tapes to be used for the backup. It displays the data set name, volume serial number, and current expiration date of the backup tape mounted; you must manually insure that the tapes are in scratch status. The data set name to be placed in the tape labels can be specified.

The backups produced by SAR can be restored by SAR, FDR, or ABR. Individual data sets can also be restored from this backup using DSF or ABR. However, VSAM files cannot be restored by cluster name.

Note

Although tapes created by SAR are logically equivalent to

FDR

tapes, there are formatting differences, so they cannot be successfully compared to tapes created with

FDR

or ABR.

CLIP operations

CLIP stands for Change Label In Place. A SAR CLIP changes the volume serial number in the label track (cylinder 0 track 0) of a DASD volume. SAR prompts for the existing serial number and the new serial number. This procedure does not affect any other data on the volume. However, if the volume serial is changed on a volume containing ICF VSAM clusters or SMS-managed data sets, that data is not accessible.

CLIP works only on initialized volumes, that is, those containing a volume label and VTOC.

Data set and absolute track operations

You can specify that SAR is to back up or restore specific tracks or backup specific data sets. Since these features are rarely used, documentation can be found in member $$SAR in the FDR Installation Control Library (ICL).

VM support

SAR can be IPL’d on a VM virtual machine. See the member $$SAR in the FDR Installation Control Library (ICL) for details on VM usage.

DASD support

SAR automatically determines the type and model of DASD being dumped or restored. For emulated DASD, SAR identifies the model that the DASD emulates.

SAR cannot restore to a DASD volume with a different geometry (tracks/cylinder and track capacity), such as 3380 to 3390, but it is able to restore to a larger capacity DASD with the same device geometry (same DASD type), for example, from a backup of a 3390-3 to a 3390-9. SAR automatically recognizes whether the output volume being restored is the same capacity as the volume that was backed up. If the volume being restored to is larger, SAR turns on the DOS bit; the first time a data set is allocated on that volume after the system is IPL’d, the system calls the VTOC conversion routine, which rebuilds the VTOC to reflect the larger amount of available space. If the volume contained an indexed VTOC, the index is disabled and you must use ICKDSF to rebuild the index after IPL.

Normally, SAR does not allow you to restore a backup to a model with a smaller capacity than the DASD volume that was backed up. However, as long as there were no data sets allocated on the original DASD volume beyond the end of the target DASD volume, you can force SAR to restore a higher capacity DASD to a lower capacity DASD of the same type. You must override the device type that SAR has correctly determined and substitute the type that was backed up. For example, if your backup was created from a 3390-9 and you want to restore to a 3390-3, then specify OUTPUT DISK DEVICE=3390-9.

Warning

Restore to a smaller DASD only works if all of the allocated tracks on the original DASD are contained within the physical capacity of the output DASD. Otherwise, SAR gives various error messages. We recommend that this type of restore be done only if no other options are available.

Tape support

SAR RESTORE automatically supports tapes that were compressed by the software data compression feature of FDR (COMPRESS=). There are no special considerations. SAR cannot create a tape with FDR compression, but it can read and create cartridges that are compressed by the tape hardware.

For restore, SAR automatically requests the second and subsequent tape volumes if more than one volume was used on the backup; however, the operator must know what tape volumes are required for the restore of a particular DASD volume and mount them in the proper order. During backup, SAR requests a new scratch output tape be mounted if the current volume is full. In either case, a message is issued to the console requesting the next volume. SAR automatically recognizes when the new volume has been mounted and continues with the operation.

It is the operator’s responsibility to ensure that the required input or output tapes are mounted in the correct order, and to record the volume serials of output tapes. If you are restoring from ABR full-volume backups, an FDRABRP “PRINT CATLG” report can be used to identify the tapes required for the restore.

If your cartridge tape drive has an automatic cartridge loader (ACL) you can load the tapes required into the ACL before the SAR operation is started. The ACL cannot be in system mode. If it is in automatic mode, the next tape is automatically loaded when the previous tape is unloaded by SAR. In manual mode, the operator must press START to load each cartridge.

If the required tape volumes are in an Automated Tape Library (ATL) such as the IBM 3494/3495 and Oracle StorageTek silos, special procedures may be required to mount the tapes required for the backup or restore. The SAR IPL tape can also be in the ATL. Please consult your ATL vendor's documentation for details:

The IBM 3494 supports a “stand-alone mode” for a given drive, selected from the library console. In that mode you tell it the tape volumes to mount, and it fetches and mounts them automatically. Tapes can also be inserted from outside the library (such as the SAR IPL tape).
The IBM 3495 and Oracle StorageTek silos must be placed in manual mode, allowing entry to the enclosure and manually mount tapes. If the required tapes are in the library, they must be located and manually mounted. The 3495 has a locate function on its “manual mode” console, while Oracle StorageTek has an IPLable utility called “POST VOLSER to Location” that identifies tape locations.
To mount a tape in the IBM TS3500 tape library (also called 3584), use the GUI to “move” the tape to the desired tape drive. In the GUI, the user specifies the tape drive by relative location (drive 1, drive 2, etc.); be aware that the relative locations are not necessarily in the same order as the MVS device addresses. For example, drive 1 may be address C02 and drive 2 may be address C00.

If the required tape is in a hardware Virtual Tape System (VTS) you may be able to manually mount the virtual tape volumes on a virtual drive; consult your VTS vendor's documentation. SAR cannot use virtual volumes in a software-only VTS.

SAR supports both SL (standard label) and NL (non-labeled) tapes. Since almost all backup tapes are labeled, documentation on the use of NL tapes is only in the member $$SAR in the FDR Installation Control Library (ICL).

Console support

SAR requires a console for input and output. Any 3270-compatible real or emulated display terminal that can be used as a standard z/OS MCS operator console is supported by SAR.

SAR supports printer/keyboard consoles, which display one line at a time (see the member $$SAR in the FDR Installation Control Library (ICL) for details). In addition, SAR supports the limited-function operator message facility on the HMC, known as the “SCLP Console” as a printer/keyboard-type console. For instructions, see SCLP Console in SAR-Operation-Requirements.

Error recovery

Some errors cause immediate termination of the current SAR function, but SAR is able to continue after certain types of errors. If an error occurs, SAR displays a message detailing the error. If SAR is able to continue, the message includes the text “REPLY CONTINUE OR TERM” and you are prompted for a response. If you reply CONTINUE (or just press ENTER since CONTINUE is the default), SAR continues; however, depending on the error, data may be lost (not dumped or restored). If you reply TERM, SAR terminates its current operation, enabling you to restart SAR for another function. If you have a hard copy device assigned, and you want a dump of SAR's memory for diagnostic purposes, you can use the PSW RESTART hardware function to obtain such a dump before replying.